Centering-cap for boring-tools.



A. DE VILBISS.

(ENTERING GAP FOR BORING TOOLS.

APPLICATION FILEDNOV. 25, 1911.

1,043,408.. Patented Nov. 5, 1912.

' WZ'TNESEEE' JNTENTUR.

UNITE STATES 'ATENT QFFTCE.

CENTERING-CAP FOR BORING-TOOLS.

Application filed November 25, 1911.

To all whom it may concern! Be it known that I, ALLEN DE VILBISS, a

citizen of the United States, and a resident of Toledo, in the county of Lucas and State of Ohio, have invented a certain new and useful Centering-Cap for Boring-Tools; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the figures of reference marked thereon, which form a part of this specification.

My invention relates particularly to trephining tools, but is not restricted to such use as it may be used for any purpose for which it is applicable.

It has been customary in tools of this class to provide the bits thereof with interiorly disposed centering pins, which are longitudinally adjustable therein to axially project their cutting ends or points from the bitheads or to retract the same therein when a hole has been started, the control parts for such adjustments being usually disposed to the rear of the bit-head.

The object of my invention is the provision of improved centering means for tools of this character, which means is simple and inexpensive in its construction, and is capable of being easily and quickly applied to the cutting heads of any of the tools of this character commonly employed, and which obviates the necessity of axially drilling the tools for the reception of the centering pins hereto-fore used.

The invention is fully described in the following specification, and while, in its broader aspect, it is capable of embodiment in numerous forms, a preferred embodiment thereof is illustrated in the accompanying drawings, in which,-

Figure 1 is a side elevation of a tool equipped with my invention. Fig. 2 is a similar view thereof with the centering cap removed, and Figs. 3 and 4 are outer and inner end views respectively of the centering cap.

Referring to the drawings, 1 designates the shank and 2 the cutter-head of a trephining tool or bit of the usual form, 3 a center ing cap comprising my invention, and 4 a skull or other bone upon which the tool is operating. The cutter-head 2 of tools of this character is usually of truncated-cone Specification of Letters Patent.

Patented Nov. 5, 1912.

Serial No. 662,524.

form and provided with a series of spirally arrange-d cutting edges or teeth 2-, as shown. The centeringcap 3 is preferably of cylindrical form and has its inner end socketed in conical form, as indicated at 5, for the cutter-head 2 to snugly seat in, and is provided on its interior side wall with preferably a single stud or tooth 6, which interengages with the teeth of the cutter-head to cause said parts to rotate in unison. The outer end of the cap is flattened, as at 7, and is provided diametrically thereof with a starting-blade 8 from the center of which axially projects a centering point 9. The blade 8 is substantially equal in length to the diameter of the outer end of the cutterhead to enable such end of the head to seat closely within a hole or socket started by said blade. The outer end of the cap 3 is preferably slightly larger in diameter than the length of the blade 8 to provide a shoulder 10 at the ends thereof for limiting the depth of cut of the blade, as is apparent, thus providing a positive stop for the cutting action of the cap when the hole being bored is of suitable predetermined depth.

It is evident that my improved centering means for trephining bits or the like can be easily and quickly applied to or removed from a bit, and obviates not only the expense incident to the use of the types of centering means now used, but also the inconvenience and annoyance of the present method of adjusting such means to place it in starting and retracted or inoperative positions.

I wish it understood that my invention is not limited to use in connection with any particular form of cutter-head or manner of interengaging therewith, nor is it limited to any specific construction or arrangement of the parts, except in so far as such limitations are specified in the claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is,

1. The combination with a boring bit, of a centering-cap capable of being removably carried by the bit-head and having a starting blade disposed transverse to the bit axis.

2. The combination with a boring bit, of a centering-cap having its inner end socketed to receive and interengage the bit-head and its outer end provided with a centering and starting blade.

3. The combination with a boring bit, of

a centering-cap capable of being removably carried by the bit and having a centering and starting blade at its outer end Which is shorter than the Width of such end to limit the depth of cut thereof.

4. In a trephining tool, the combination with a conical cutter-head, of a centeringcapsocketed at one end to receive said outter-head and provided interiorly of said socket with means for inter-engaging with the cutter-head teeth and having a centering and starting blade at its opposite end.

5. In a trephining tool the combination with a cutter-head, of a centering-cap having a socket in one end for removably receiving said cutter-head and interengaging therewith to prevent a relative rotation thereof, and having a transversely disposed centering and starting blade at its opposite end Which terminates at its ends short of the edges of the associatedcap end to provide a stop shoulder.

In testimony whereof, I have hereunto signed my name to this specification inthe presence of two subscribing Witnesses.

ALLEN DE VILBISS.

Witnesses:

S. T. KLoTz, C. W. OWEN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents Washington, D. G. 

